1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_S390_JUMP_LABEL_H 3 #define _ASM_S390_JUMP_LABEL_H 4 5 #ifndef __ASSEMBLY__ 6 7 #include <linux/types.h> 8 #include <linux/stringify.h> 9 10 #define JUMP_LABEL_NOP_SIZE 6 11 #define JUMP_LABEL_NOP_OFFSET 2 12 13 #if __GNUC__ < 9 14 #define JUMP_LABEL_STATIC_KEY_CONSTRAINT "X" 15 #else 16 #define JUMP_LABEL_STATIC_KEY_CONSTRAINT "jdd" 17 #endif 18 19 /* 20 * We use a brcl 0,2 instruction for jump labels at compile time so it 21 * can be easily distinguished from a hotpatch generated instruction. 22 */ 23 static inline bool arch_static_branch(struct static_key *key, bool branch) 24 { 25 asm_volatile_goto("0: brcl 0,"__stringify(JUMP_LABEL_NOP_OFFSET)"\n" 26 ".pushsection __jump_table,\"aw\"\n" 27 ".balign 8\n" 28 ".long 0b-.,%l[label]-.\n" 29 ".quad %0+%1-.\n" 30 ".popsection\n" 31 : : JUMP_LABEL_STATIC_KEY_CONSTRAINT (key), "i" (branch) : : label); 32 return false; 33 label: 34 return true; 35 } 36 37 static inline bool arch_static_branch_jump(struct static_key *key, bool branch) 38 { 39 asm_volatile_goto("0: brcl 15,%l[label]\n" 40 ".pushsection __jump_table,\"aw\"\n" 41 ".balign 8\n" 42 ".long 0b-.,%l[label]-.\n" 43 ".quad %0+%1-.\n" 44 ".popsection\n" 45 : : JUMP_LABEL_STATIC_KEY_CONSTRAINT (key), "i" (branch) : : label); 46 return false; 47 label: 48 return true; 49 } 50 51 #endif /* __ASSEMBLY__ */ 52 #endif 53